Multiple systems adaptive television receiver

Abstract

A multiple systems adaptive television receiver which is able to receive different system television signals such as the PAL system, the NTSC system, the SECAM system including a chrominance signal and a unique ID signal of the different television signals. The television receiver includes an ACC circuit for stabilizing the amplitude of the chrominance signal by the identification signal, the ACC circuit including a detector for detecting the ID signal, at least two ID discriminators each dedicated for discriminating the unique ID signal obtained by the ACC circuit, a control circuit for assigning priority of discriminating sensitivity to the each ID discriminator and a circuit for increasing the sensitivity of the each ID discriminator in response to an information for stabilizing the chrominance signal and an output from the active one of the ID discriminators.

What is claimed is: 
     
       1. A multiple systems adaptive television receiver which is able to receive at least two different system television signals, each including a chrominance signal and a unique identification signal of the different television signals, comprising: means for stabilizing the amplitude of the chrominance signal of the received television signal by the identification signal, the stabilizing means including means for detecting the identification signal;   at least two means each dedicated for discriminating the unique identification signal obtained by the stabilizing means;   means for assigning priority of discriminating sensitivity to the each discriminating means; and   means for increasing the sensitivity of the each discriminating means in response to an information for stabilizing the chrominance signal and an output from the active one of the discriminating means.   
     
     
       2. A multiple systems adaptive television receiver which is able to receive at least two different system television signals, each including a chrominance signal and a unique identification signal of the different television signals, comprising: an ACC circuit for stabilizing the amplitude of the chrominance signal by the identification signal of the received television signal, the stabilizing means including means for detecting the identification signal;   a color synchronous reproduction circuit which produces first and second continuous waves synchronized to a burst signal from the ACC circuit, a killer detection circuit which synchronously detects the first continuous wave from the color synchronous reproduction circuit and the output burst signal from the ACC circuit, a signal level comparison circuit which, upon comparing a detection output of the killer detection circuit with a specified reference signal level, detects when a synchronous detection output has exceed the reference signal level, a color difference demodulation circuit which demodulates the chrominance signal from the ACC circuit by the second continuous wave of the color synchronous reproduction circuit, a means which shuts off the chrominance signal route with the output from the level comparison circuit to prevent the demodulation signal from appearing in the output from the demodulation circuit, and a means which controls detection sensitivity of the killer detection circuit or reference voltage of the level comparison circuit when control information of the ACC circuit and detection output information of the killer detection circuit satisfy required conditions.   
     
     
       3. The multiple systems adaptive television receiver as claimed in claim 2, wherein the detection sensitivity of the killer detection circuit is controlled by an AND logic function involving control information recognizing that the ACC circuit is receiving television signals and detection output information recognizing a presence of a synchronously detected burst component in the detection output of the killer detection circuit. 
     
     
       4. The multiple systems adaptive television receiver as claimed in claim 2, wherein a reference voltage of the level comparison circuit is controlled by an AND logic function involving control information recognizing that the ACC circuit is receiving television signals and detection output information recognizing presence of a synchronously detected burst component in the output of the killer detection circuit. 
     
     
       5. The multiple systems adaptive television receiver as claimed in claim 2, wherein: the killer detection circuit cuts off a load resistance from the killer detection circuit for a horizontal period by applying an output current from the killer detection circuit to a holding capacitor and a load resistor of which one side is connected to a first reference voltage source;   the level comparison circuit including a first differential pair to detect a potential difference between a voltage of the holding capacitor and a second reference voltage source;   second and third differential pairs for detecting a potential difference between the first reference voltage and a holding capacitor voltage, and for outputting an output of the first differential pair as the detection output of the killer detection circuit;   first and second switching means for selecting outputs from the second and third differential pairs according to ACC control information;   means for controlling the detection sensitivity of the killer detection circuit by operation of the first switching means; and   means for controlling a voltage of the second reference voltage source by operation of the second switching means.